class Person
	attr_accessor :first_name, :middle_name, :last_name
	def whole_name
		n = first_name + " "
		n << "#{middle_name} " if middle_name
		n << last_name
	end 
end 
david = Person.new
david.first_name = "David"
david.last_name = "Black"
puts "David's whole name: #{david.whole_name}"
david.middle_name = "Alan"
puts "David's new whole name: #{david.whole_name}"